The present invention is generally directed to an electronic device that can be incorporated into or used in conjunction with a generic transmitter to perform a number of channel optimizations on an arbitrary signal prior to the signal being amplified by a downstream power amplifier.
FIG. 1 provides an example of a generic transmitter 100 that can be configured to receive an analog input signal from a baseband processor or modulator 105, perform necessary processing on the signal, and then output the processed signal to an antenna 110 for transmission. Generic transmitter can include a frequency upconverter (or mixer) 100a to convert the analog input signal to the proper frequency (assuming the signal generated by modulator 105 is not already at the proper frequency), a variable gain control 100b (e.g., amplifier, attenuator or combination of both), and a power amplifier 100c for amplifying the upconverted signal prior to transmission.
When output from modulator 105, the analog input signal typically will have little to no distortion. However, the components of transmitter 100 will typically introduce distortion in various forms including group delay variation, nonlinear distortion, and frequency flatness among others. This is especially true when the input signal is a wideband signal (e.g., a signal having a bandwidth between 500 MHz and 1 GHz). Although a number of techniques exist for accounting for the distortion introduced by transmitter 100, it can be difficult to successfully account for all distortion especially in wide bandwidth systems.